The inventive concept relates to a semiconductor device, and more particularly, to a semiconductor device including buried word lines.
As the degree of integration of semiconductor devices increases, design rule parameters for elements included in the semiconductor devices are being reduced. In particular, in semiconductor devices requiring a large number of transistors, a gate length, which is one of the design rule parameters, is being reduced and accordingly, a channel length is also being decreased. To increase an effective channel length by extending the distance between a source and a drain in a transistor of a highly-scaled semiconductor device, buried gate type transistors have been introduced. In a buried gate type transistor, a trench is formed in a substrate and a gate of the transistor is formed in the trench.